Accessory for a self-balancing board

ABSTRACT

An accessory for a self-balancing board is provided. The self-balancing board comprises a foot-deck having two lateral foot-deck ends. Each lateral foot-deck end is coupled to a motor that drives a wheel in response to an orientation of the lateral foot-deck end relative to a horizontal plane. The accessory includes a chassis, at least one travel surface-contacting element coupled proximal to a first longitudinal end of the chassis to facilitate travel of the chassis over a travel surface, and a seat coupled to the chassis and configured to support a person. The accessory further includes a first foot-deck engagement element proximal to a second longitudinal end of the chassis distal to the first longitudinal end and constructed to engage the foot-deck of the self-balancing board proximal to the first lateral foot-deck end, and a second foot-deck engagement element proximal to the second longitudinal end of the chassis and constructed to engage the foot-deck of the self-balancing board proximal to the second lateral foot-deck end. At least one control member coupled to the first foot-deck engagement element and the second foot-deck engagement element controls the orientation of the lateral foot-deck ends relative to a horizontal plane via the first foot-deck engagement element and the second foot-deck engagement element.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/423,564, filed on Feb. 2, 2017, the contents of which areincorporated herein by reference in their entirety.

FIELD

The specification relates generally to powered personal transportationdevices. In particular, the following relates to an accessory for aself-balancing board.

BACKGROUND OF THE DISCLOSURE

Self-balancing boards are well known in the industry. Suchself-balancing boards, however, require considerable effort and skillfor a rider to safely balance themselves while riding such boards. Inaddition, instability is inherent and thus a closed-loop feedbackcontrol system is required in order to maintain balance. This meansthat, if at any moment, the control effort is inadequate, the rider caneasily fall from the vehicle. This can be the result of a malfunction ofthe vehicle, or by the rider providing an extreme, inadequate, or overinput, such as a lean angle that would result in an output (such as adesired wheel torque or speed) that is beyond the capability of thevehicle or the rider's ability to self-balance on the self-balancingboard. In either case, if the output required to maintain balance is notachievable, the rider will likely fall, potentially causing injuries tothemselves or others, or property damage. When the rider does fall, therisk of bodily injury is high due to the height of the standing userfrom the ground. There have been numerous documented incidents whereriders have fallen off of self-balancing boards, leading to injuriesthat range from minor scrapes all the way to broken bones andconcussions.

SUMMARY OF THE DISCLOSURE

In one aspect, there is provided an accessory for a self-balancingboard, the self-balancing board comprising a foot-deck having twolateral foot-deck ends, each lateral foot-deck end being coupled to amotor that drives a wheel in response to an orientation of the lateralfoot-deck end relative to a horizontal plane, the accessory comprising achassis, at least one travel surface-contacting element coupled proximalto a first longitudinal end of the chassis to facilitate travel of thechassis over a travel surface, a seat coupled to the chassis andconfigured to support a person, a first foot-deck engagement elementproximal to a second longitudinal end of the chassis distal to the firstlongitudinal end and constructed to engage the foot-deck of theself-balancing board proximal to the first lateral foot-deck end, asecond foot-deck engagement element proximal to the second longitudinalend of the chassis and constructed to engage the foot-deck of theself-balancing board proximal to the second lateral foot-deck end, andat least one control member coupled to the first foot-deck engagementelement and the second foot-deck engagement element to control theorientation of the lateral foot-deck ends relative to a horizontal planevia the first foot-deck engagement element and the second foot-deckengagement element.

The at least one control member can comprise at least one control leverbeing coupled to the first foot-deck engagement element and the secondfoot-deck engagement element to control pivoting of the first foot-deckengagement element and the second foot-deck engagement element.

The accessory can further comprise a bridging member coupled to thefirst foot-deck engagement element and the second foot-deck engagementelement to control pivoting of the first foot-deck engagement elementand the second foot-deck engagement element relative to one another.

The at least one control lever can comprise a first control levercoupled to the first foot-deck engagement element and the secondfoot-deck engagement element to thereby control simultaneous pivoting ofthe first foot-deck engagement element and the second foot-deckengagement element.

The at least one control lever can comprise a first control levercoupled to the first foot-deck engagement element and a second controllever coupled to the second foot-deck engagement element.

The first foot-deck engagement element can be independently pivotablerelative to the second foot-deck engagement element about a controlpivot axis that is generally parallel to the rotation axis of the wheelsof the self-balancing board.

Each of the first foot-deck engagement element and the second foot-deckengagement element can comprise an interface member constructed tointerface with the foot-deck proximal to one of the lateral foot-deckends and having at least two degrees of freedom of movement relative tothe chassis.

Each of the first foot-deck engagement element and the second foot-deckengagement element can further comprise a control foot that isindependently pivotable relative to the chassis about the control pivotaxis that is generally parallel to the rotation axis of the wheels ofthe self-balancing board and is movably coupled to the interface memberto enable movement of the control foot relative to the interface member.

The control foot can be pivotally coupled to the interface member abouta torque pivot axis that is generally perpendicular to the control pivotaxis.

The first foot-deck engagement element can be constructed to secure tothe foot-deck of the self-balancing board proximal to the first lateralfoot-deck end and the second foot-deck engagement element can beconstructed to secure to the foot-deck of the self-balancing boardproximal to the second lateral foot-deck end.

The first foot-deck engagement element can be constructed to releasablysecure to the foot-deck of the self-balancing board proximal to thefirst lateral foot-deck end and the second foot-deck engagement elementcan be constructed to releasably secure to the foot-deck of theself-balancing board proximal to the second lateral foot-deck end.

Each of the first foot-deck engagement element and the second foot-deckengagement element can comprise a fastener for releasably securing theinterface member against the foot-deck. The interface member cancomprise the fastener. The fastener can comprise at least one of astrap, a clamp, and a magnetic element.

The control foot can be pivotally secured to the interface member. Thefastener can couple directly to the control foot. The fastener cancomprise at least one of a strap, a clamp, and a magnetic element. Theinterface member can comprise features restricting movement of thecontrol foot relative to the interface member within a desired range.

Each of the control levers can be adjustably coupled to one of thefoot-deck engagement elements and lockable in one of a set oforientations relative to the one foot-deck engagement element.

The interface member can comprise laterally extending lips that areconstructed to overhang front and rear edges of the foot-deck to preventmovement of the interface member relative to the foot-deck.

The seat can be positioned proximal to the second end.

A position of the seat longitudinally along the chassis can beadjustable.

The at least one travel surface-contacting element can be a freelyspinning wheel.

The accessory can further comprise a biasing structure biasing one ofthe first foot-deck engagement element and the at least one controllever to a position relative to the chassis wherein the foot-deck of theself-balancing board is unbiased away from a generally horizontalorientation when the accessory is positioned thereon.

The biasing structure can comprise at least one biasing spring biasingthe one of the first foot-deck engagement element and the at least onecontrol lever relative to the chassis.

The first foot-deck engagement element and the second foot-deckengagement element can be constructed to avoid contact with a centralregion of the foot-deck when the accessory is positioned thereon. Thefirst foot-deck engagement element and the second foot-deck engagementelement can have gaps positioned on the central region of the foot-deckwhen the accessory is positioned thereon.

In another aspect, there is provided a method of using a self-balancingboard, comprising placing a first foot-deck engagement element of anaccessory on a foot-deck of a self-balancing board proximal to a firstlateral foot-deck end thereof, the self-balancing board furthercomprising a second lateral foot-deck end of the foot-deck, each of thefirst lateral foot-deck end and the second lateral foot-deck end beingcoupled to a motor that drives a wheel in response to an orientation ofthe lateral foot-deck end relative to a horizontal plane, the accessoryfurther comprising a chassis having a first longitudinal end, and asecond longitudinal end proximal to the first foot-deck engagementelement, at least one travel surface-contacting element coupled proximalto a first longitudinal end of the chassis to facilitate travel of thechassis over a travel surface, a seat coupled to the chassis andconfigured to support a person, a second foot-deck engagement elementproximal to the second longitudinal end of the chassis, and at least onecontrol member coupled to the first foot-deck engagement element and thesecond foot-deck engagement element to control the orientation of thelateral foot-deck ends relative to a horizontal plane via the firstfoot-deck engagement element and the second foot-deck engagementelement, and placing the second foot-deck engagement element on thefoot-deck of the self-balancing board proximal to a second lateralfoot-deck end thereof.

The at least one control member can comprise at least one control leverbeing coupled to the first foot-deck engagement element and the secondfoot-deck engagement element to control pivoting of the first foot-deckengagement element and the second foot-deck engagement element.

The method can further comprise releasably securing the first foot-deckengagement element to the first lateral foot-deck end, and releasablysecuring the second foot-deck engagement element to the second lateralfoot-deck end.

BRIEF DESCRIPTIONS OF THE DRAWINGS

For a better understanding of the various embodiments described hereinand to show more clearly how they may be carried into effect, referencewill now be made, by way of example only, to the accompanying drawingsin which:

FIG. 1 is a perspective view of one type of a self-balancing board;

FIG. 2 is a perspective view of an accessory for the self-balancingboard of FIG. 1 in accordance with an embodiment;

FIG. 3 is a side view of the accessory of FIG. 2;

FIG. 4 is a front view of the accessory of FIG. 2;

FIG. 5 is a top view of the accessory of FIG. 2;

FIG. 6 is a partially exploded perspective view of the accessory of FIG.2;

FIG. 7 is a partially exploded perspective view of a portion of afoot-deck engagement element and a control lever of the accessory ofFIG. 2 aligned with a portion of the foot-deck of the self-balancingboard of FIG. 1;

FIG. 8 is another partially exploded perspective view of the portion ofa foot-deck engagement element and the control lever of the accessory ofFIG. 2 aligned with a portion of the foot-deck of the self-balancingboard of FIG. 1;

FIG. 9 shows a perspective view of the portion of the foot-deckengagement element of the accessory of FIG. 2 aligned with a portion ofthe foot-deck of the self-balancing board of FIG. 1;

FIG. 10 is a perspective view of the foot-deck engagement element of theself-balancing board of FIG. 2 aligned with a portion of the foot-deckof the self-balancing board of FIG. 1;

FIG. 11 is a perspective view of the accessory of FIG. 2 aligned withthe self-balancing board of FIG. 1;

FIG. 12 is a perspective view of the accessory of FIG. 2 secured to theself-balancing board of FIG. 1;

FIG. 13 is a perspective view of the accessory of FIG. 2 secured to theself-balancing board of FIG. 1 wherein the chassis has been extendedlongitudinally;

FIG. 14 is a perspective view of the accessory of FIG. 2 secured to theself-balancing board of FIG. 1, wherein the seat has been positionedforward;

FIG. 15 is a perspective view of the accessory of FIG. 2 secured to theself-balancing board of FIG. 1, wherein the control levers have beenadjusted to a different angular position;

FIG. 16 is a top view of the accessory of FIG. 2 secured to theself-balancing board of FIG. 1, wherein a control lever has been movedand a control foot pivoted relative to the interface member;

FIG. 17 is a perspective view of an accessory for use with theself-balancing board of FIG. 1 in accordance with another embodiment,wherein the interface members have gaps that are positioned on thecentral region of the foot-deck when the accessory is positionedthereon;

FIG. 18A is a partial exploded view of a biasing spring for biasing acontrol lever of an accessory for use with the self-balancing board ofFIG. 1 in accordance with yet another embodiment;

FIG. 18B is a partial assembled view of the biasing spring and accessoryof FIG. 18A; and

FIG. 19 is a perspective view of an accessory for the self-balancingboard of FIG. 1 in accordance with a still further embodiment.

REFERENCE NUMBER INDEX

-   -   10 self-balancing board    -   11 platform    -   12 wheel    -   13 foot-deck    -   14 lateral foot-deck end    -   15 front foot-deck edge    -   16 rear foot-deck edge    -   20 accessory for a self-balancing board    -   24 chassis    -   28 front cross-bar    -   30 front longitudinal end    -   32 longitudinal extension tube    -   36 telescoping longitudinal tube    -   40 locking knob    -   44 rear cross-bar    -   46 rear longitudinal end    -   48 foot rest    -   52 front wheel assembly    -   56 seat    -   60 top seat mounting bracket    -   64 bottom seat mounting bracket    -   68 seat mounting locking knob    -   72 foot-deck engagement element    -   76 control lever    -   80 control lever pivot bracket    -   84 control grip    -   FP front pivot axis    -   88 interface member    -   90 underside surface    -   92 laterally extending lip    -   96 top recess    -   100 lateral ridge    -   104 torque pivot post    -   108 control foot    -   112 pivot post aperture    -   116 positioning arch    -   120 pivot through-hole    -   124 position teeth    -   128 strap engagement hook    -   132 control lever pivot through-hole    -   136 pivot bolt    -   140 positioning lock release lever    -   CP control pivot axis    -   TP torque pivot axis    -   144 cinch strap    -   150 accessory    -   154 interface member    -   158 thicker end    -   162 gap    -   170 accessory    -   172 control lever    -   174 control lever pivot bracket    -   176 control pivot through-hole    -   178 pin-hole    -   180 pivot bolt    -   182 bolt head    -   184 deep slot    -   186 threaded hole    -   188 threaded screw    -   190 biasing spring    -   192 cross-portion    -   194 angled coil end    -   200 accessory    -   204 chassis    -   208 longitudinal extension tube    -   212 telescoping longitudinal tube    -   216 locking knob    -   220 rear cross-bar    -   224 pivot bracket    -   228 head assembly    -   232 head pivot bolt    -   236 front cross-bar    -   240 foot rest    -   244 front wheel assembly    -   248 seat    -   252 seat mounting bracket    -   256 master foot-deck engagement element    -   260 interface member    -   264 control foot    -   268 positioning arch    -   272 strap engagement hook    -   276 control lever    -   280 control lever pivot bracket    -   284 control grip

DETAILED DESCRIPTION

For simplicity and clarity of illustration, where consideredappropriate, reference numerals may be repeated among the Figures toindicate corresponding or analogous elements. In addition, numerousspecific details are set forth in order to provide a thoroughunderstanding of the embodiments described herein. However, it will beunderstood by those of ordinary skill in the art that the embodimentsdescribed herein may be practiced without these specific details. Inother instances, well-known methods, procedures and components have notbeen described in detail so as not to obscure the embodiments describedherein. Also, the description is not to be considered as limiting thescope of the embodiments described herein.

Various terms used throughout the present description may be read andunderstood as follows, unless the context indicates otherwise: “or” asused throughout is inclusive, as though written “and/or”; singulararticles and pronouns as used throughout include their plural forms, andvice versa; similarly, gendered pronouns include their counterpartpronouns so that pronouns should not be understood as limiting anythingdescribed herein to use, implementation, performance, etc. by a singlegender; “exemplary” should be understood as “illustrative” or“exemplifying” and not necessarily as “preferred” over otherembodiments. Further definitions for terms may be set out herein; thesemay apply to prior and subsequent instances of those terms, as will beunderstood from a reading of the present description.

Accessories for self-balancing boards are provided. The self-balancingboards have a foot-deck having two lateral foot-deck ends. Each lateralfoot-deck end is coupled to a motor that drives a wheel in response toan orientation of the lateral foot-deck end relative to a horizontalplane. The accessory includes a chassis, at least one travelsurface-contacting element coupled proximal to a first longitudinal endof the chassis to facilitate travel of the chassis over a travelsurface, and a seat coupled to the chassis and configured to support aperson. A first foot-deck engagement element is proximal to a secondlongitudinal end of the chassis distal to the first longitudinal end andis constructed to engage the foot-deck of the self-balancing boardproximal to the first lateral foot-deck end. A second foot-deckengagement element is proximal to the second longitudinal end of thechassis and is constructed to engage the foot-deck of the self-balancingboard proximal to the second lateral foot-deck end. At least one controlmember is coupled to the first foot-deck engagement element and thesecond foot-deck engagement element to control the orientation of thefirst and second lateral foot-deck ends relative to a horizontal planevia the first foot-deck engagement element and the second foot-deckengagement element.

The accessories use the self-balancing boards in a manner that differsfrom the method in which they were originally intended to be used. Byadding at least one additional travel surface-contacting element, arider may place their center of gravity over the area between the twowheels of the self-balancing board and the at least one travelsurface-contacting element, thereby providing a stable stage to rideupon while still using the motor means of the self-balancing board topropel the self-balancing board and the accessory. Further, theaccessories enable the lateral foot-deck ends to be actuated via atleast one control member coupled to the foot-deck engagement elements tocontrol the orientation of the lateral foot-deck ends of theself-balancing board relative to a horizontal plane.

A self-balancing board 10 is shown in FIG. 1. The self-balancing board10 has a platform 11 that spans between two wheels 12. A foot-deck 13 ofthe platform 11 enables a rider to stand thereon. The foot-deck 13 isgenerally planar and may be textured and/or made from a material thatprovides traction between the foot of a rider and the platform 11. Thefoot-deck 13 has two lateral foot-deck ends 14 adjacent the wheels 12, afront foot-deck edge 15, and a rear foot-deck edge 16. The frontfoot-deck edge 15 and the rear foot-deck edge 16 represent theintersections between the front and back surfaces of the platform 11 andthe foot-deck 13.

A motor proximal to each lateral foot-deck end 14 powers the wheeladjacent to it. Each motor is operated to rotate the adjacent wheel 12based on the pitch of the lateral foot-deck end 14 relative to ahorizontal plane when the self-balancing board is upright. The platform11 may be, in some cases, split into two platform halves that can pivotrelative to each other around an axis that is generally coaxial or atleast generally parallel to the rotation axis of the wheels 12. In suchcases, the orientation of the lateral foot-deck ends 14 can bedetermined via gyroscopes, accelerometers, or the like. In other cases,the platform 11 may be constructed to permit flexing of the platform 11,thereby enabling one lateral foot-deck end 14 to pivot somewhatindependently of the other lateral foot-deck end 14 as a result oftorsion forces on the platform. The pivoting between the lateralfoot-deck ends 14 can be determined using a strain gauge or the like.

If both lateral foot-deck ends 14 are similarly pitched in onedirection, both adjacent motors will drive the self-balancing board inthat direction at a similar speed, thus causing the self-balancing boardto move in that direction. Alternatively, if both lateral foot-deck ends14 are differently pitched in the same direction, the motors will drivethe self-balancing board in that general direction, and the motoradjacent the more pitched lateral foot-deck end 14 will operate itsassociated wheel 12 more rapidly, causing the self-balancing board toturn in that direction. If one lateral foot-deck end 14 is pitched inone direction and the other lateral foot-deck end 14 is similarlypitched in the opposite direction, the motors will rotate the wheels inopposite directions, causing the self-balancing board 10 to rotate atits location.

An accessory 20 for the self-balancing board 10 of FIG. 1 in accordancewith an embodiment is shown in FIGS. 2 to 6. The accessory 20 isintended to enhance both the safety and enjoyment of the self-balancingboard by effectively converting a traditional self-balancing board intoa powered kart that, when ridden, generally lowers the rider's center ofgravity. The accessory 20 includes a chassis 24 that has a frontcross-bar 28 at a front longitudinal end 30. Two parallel longitudinalextension tubes 32 extend backward from the front cross-bar 28 and areslidingly received within two parallel telescoping longitudinal tubes 36and lockable at a number of positions via a locking knob 40. The twotelescoping longitudinal tubes 36 are adjoined to a rear cross-bar 44 ata rear longitudinal end 46 of the chassis 24. The front cross-bar 28,the longitudinal extension tubes 32, the telescoping longitudinal tubes36 and the rear cross-bar 44 can be made of any suitable material, suchas aluminum or steel. The front cross-bar 28 is secured to thelongitudinal extension tubes 32 via welding or another suitableapproach. Similarly, the telescoping longitudinal tubes 36 are securedto the rear cross-bar 44 via welding or another suitable approach.

Two foot rests 48 are secured to opposite ends of the front cross-bar28. The foot rests 48 provide a place to position one's feet so that therider's feet do not drag on a travel surface. The foot rests 48 can beused to carry the accessory 20 when it is not being ridden, either whenthe accessory 20 is secured to the self-balancing board 10 or detachedfrom it. Further, the foot rests 48 can include heel rests in otherembodiments to inhibit slippage of the rider's heels onto the travelsurface. A front wheel assembly 52 is pivotally coupled to the frontcross-bar 28 to enable the front wheel assembly 52 to swivel around afront wheel pivot axis FP that is generally vertically aligned when theaccessory 20 is upright.

A seat 56 is shown secured to the telescoping longitudinal tubes 36 ofthe chassis 24 proximal to the rear longitudinal end 46 thereof via atop seat mounting bracket 60 and a bottom seat mounting bracket 64 thatare clamped together atop of the telescoping longitudinal tubes 36 via aseat mounting locking knob 68. The seat 56 can be a basic molded seatmade of plastic or the like. Alternatively, the seat 56 can be providedwith padding and/or suspension to make the rider's experience moreenjoyable and to protect the rider from jarring while traveling overless smooth travel surfaces. The position of the seat 56 along thechassis 24 can be adjusted by loosening the seat mounting locking knob68, sliding the seat 56 forward or backward as desired, and thentightening the seat mounting locking knob 68. The seat 56 may be mountedas low as possible to reduce the height of the center of gravity. Thisalso brings the rider closer to the ground, reducing the chance ofinjury to the rider in the event of a fall.

A foot-deck engagement element 72 is pivotally coupled to each lateralend of the rear cross-bar 44 so that the foot-deck engagement elements72 pivot about a control pivot axis CP.

The accessory 20 includes a control member for controlling theorientation of the lateral foot-deck ends 14. The control members are,in this embodiment, a control lever 76 is coupled to each foot-deckengagement element 72 via a control lever pivot bracket 80. The controllever 76 is typically constructed of steel or aluminum and welded to thecontrol lever pivot bracket 80. A control grip 84 mounted on the controllever 76 enables a rider to grip and manipulate the control lever 76.

Referring now to FIGS. 1 to 10, each foot-deck engagement element 72includes an interface member 88 that is constructed to interface withthe foot-deck proximal to one of the lateral foot-deck ends. Theinterface member 88 is made of a resilient compressible material, suchas rubber, to engage the foot-deck 13 of the self-balancing board 10proximal to a lateral foot-deck end 14 thereof. The interface member 88is the portion of the accessory 20 that directly interfaces with andactuates the foot-deck. It has a generally flat underside surface 90 toenable a greater surface area of the underside surface 90 to engage thefoot-deck 13 to thereby resist slippage. Two laterally extending lips 92span the lateral width of the interface member 88 and engage the frontand back foot-deck edges 15, 16 of the platform 11 to prevent movementof the interface member 88 relative to the foot-deck 13. A generallyplanar top recess 96 is formed between two lateral ridges 100 thatextend along the longitudinal length of the foot-deck control surface88. A torque pivot post 104 extends upward from the top recess 96.

A control foot 108 is dimensioned to fit within the top recess 96 of theinterface member 88 and has a pivot post aperture 112 on its bottomsurface to receive the torque pivot post 104 of the interface member 88.The control foot 108 is the element of the assembly 20 that acts topivot the lateral foot-deck ends 14 by application of pressure on thefront and rear portions of the foot-deck. The control foot 108 can pivotabout a torque pivot axis TP that is generally perpendicular to thecontrol pivot axis CP, and defined by the torque pivot post 104 of theinterface member 88 when the control foot 108 is held against it. Thelateral ridges 100 of the interface member 88 limit movement of thecontrol foot 108 to within a desired range. The control foot 108 and thetorque pivot post 104 can be magnetized to keep the control foot 108secured to the interface member 88 during assembly to prevent theinterface member 88 from falling off of the control foot 108 duringmounting/installation of the accessory 20 to the self-balancing board10.

A positioning arch 116 having an arcuate top surface is formed on thetop surface of the control foot 108. A pivot through-hole 120 passeslaterally through the positioning arch 116. Laterally extending positionteeth 124 are formed along the top surface of the positioning arch 116.A strap engagement hook 128 is formed on the top surface of the controlfoot 108 proximal to each of its front and rear ends.

A control lever pivot through-hole 132 extends laterally through thecontrol lever pivot bracket 80. The control lever pivot bracket 80 isfitted over the positioning arch 116 and a pivot bolt 136 is insertedthrough the control lever pivot through-hole 132 and the pivotthrough-hole 120 of the control foot 108 before it is secured to therear cross-bar 44. Positioning lock release levers 140 of the controllever 76 are releasably biased, such as via a spring, to engage theposition teeth 124 to lock the angular position of the control lever 76relative to the positioning arch 116. Manual actuation of thepositioning lock release levers 140 enables pivoting of the controllever 76 about the positioning arch 116 to adjust the angular positionof the control lever 76 relative to the control foot 108, and release ofthe positioning lock release levers 140 enables them to re-engage theposition teeth 124 to thereby lock the angular position of the controllever 76.

A cinch strap 144 is secured at each end of the control foot 108 via oneof the strap engagement hooks 128. The cinch strap 144 is made from adurable, flexible material such as hook-and-loop fabric or nylon.

FIG. 11 shows the assembled accessory 20 prior to being secured to theself-balancing board 10. In order to secure the accessory 20 to theself-balancing board 10, one end of the cinch straps 144 is undone. Theinterface members 88 are then aligned with and lowered onto thefoot-deck 13 so that each interface member 88 is proximal to one of thelateral foot-deck ends 14, with the laterally extending lips 92 of theinterface members 88 overhanging the front foot-deck edges 15 and therear foot-deck edges 16. Each cinch strap 144 is then pulled underneaththe platform 11 and secured to the other strap engagement hook 128 andtightened.

FIG. 12 shows the accessory 20 after the cinch straps 144 have securedit to the self-balancing board 10. As can be seen, the cinch straps 144are tightly secured to the platform 11 of the self-balancing board 10 sothat pivoting of the control levers 76 causes the lateral foot-deck ends14 of the self-balancing board 10 to pivot.

It may also be desirable to adjust various aspects of the accessory 20for the rider. For example, the distance from the seat 56 to the footrests 48 to accommodate for a rider's height or preference can beadjusted by loosening the locking knob 40, and either pulling thelongitudinal extension tubes 32 further out of the telescopinglongitudinal tubes 36, or by sliding the longitudinal extension tubes 32further into the telescoping longitudinal tubes 36.

FIG. 13 shows the accessory 20 after extension of the longitudinalextension tubes 32 out of the telescoping longitudinal tubes 36, therebyproviding a longer chassis 24.

Another approach to changing this distance is to loosen the seatmounting locking knob 68 underneath the chassis 24, sliding the seatforward or backward, and then tightening the seat mounting locking knob68 again to retain the seat 56 in the new position.

FIG. 14 shows the seat 56 having been adjusted forward. As can be seen,the center of gravity of the rider is shifted forward. It can beadvantageous in some scenarios to shift the rider's weight more to thefront wheel assembly 52, thereby reducing the chance that the accessory20 will not tip up (perform a “wheelie”) under strong acceleration viathe self-balancing board 10. In other scenarios, it may be desirable tomove the seat 56 backwards to facilitate the performance of “wheelies”using the accessory 20, which may be desirable for some less risk-averseor more skilled riders.

As will be appreciated, the length of the rider can be compensated forby adjusting both the extension of the longitudinal extension tubes 32relative to the telescoping longitudinal tubes 36 and by adjusting thepositioning of the seat 56 along the chassis 24.

Yet another way in which the accessory 20 can be customized for a rideris by adjusting the angular position of the control levers 76 and thusthe height of the control grips 84. This is done on each side bymanually pressing together the positioning lock release levers 140,pivoting the control lever 76 to a desired angular position, and thenreleasing the positioning lock release levers 140 so that they canre-engage the position teeth 124 at the new angular position. Theposition teeth 124 define a number of angular positions in which thecontrol levers 76 can be locked.

FIG. 15 shows the accessory 20 after adjustment of the control levers 76to a different angular position. As shown, the control levers 76 havebeen pivoted about the control pivot axis and engage position teeth thatare further back around the positioning arch from those engaged in theangular position of the control levers 76 shown in FIG. 12.

Referring now to FIGS. 7 to 12, operation of the accessory 20 will nowbe described. When the accessory 20 has been secured to theself-balancing board 10 and a rider is sitting in the seat 56, part ofthe weight of the rider is distributed to the self-balancing board 10via the interface members 88. This helps to reduce slippage of theinterface members 88 relative to the foot-deck 13. The control levers 76are secured to the control feet 108, and both pivot about the controlpivot axis P that is coaxial with the rear cross-bar 44 of the chassis24. The interface members 88 are held firmly in place atop of thefoot-deck 13 by the tension of the cinch straps 144. Forward andbackward shifting of the control feet 108 within the top recess 96 isalso inhibited by the torque pivot posts 104 being inserted in the pivotpost apertures 112 of the control feet 108, and by the longitudinal(front to rear) length of the control feet 108 in combination with thetautness of the cinch straps 144.

When a rider is in the seat 56 of the accessory 20, the rider can causeeither wheel 12 of the self-balancing board 10 to which the accessory 20is secured to accelerate in either a forward or backward direction. Thisis achieved by using the corresponding control lever 76 as a lever topivot the lateral foot-deck end 14. The control levers 76 freely pivotrelative to the chassis 24. Pivoting the control lever 76 in a directionapplies a torqueing force to the corresponding lateral foot-deck end 14by the force of the longitudinal end of the control foot 108corresponding to the direction in which the control lever 76 is beingpivoted on the lateral foot-deck end 14, and by the tension of the cinchstrap 144.

The control levers 72 can be pivoted in either a forward or backwarddirection. Pivoting both control levers 76 by the same degree and in thesame direction causes the wheels 12 to accelerate or decelerate in thedirection to which the control levers are being pivoted 76. Thus, arider can elect to accelerate or decelerate in a forward direction or abackward direction, or stop.

Additionally, a rider can elect to pivot each control lever 76 todiffering angles to cause a difference in the speed of the wheels 12,thereby causing the combined self-balancing board 10 and the accessory20 secured thereto to turn as it travels. The rider can even rotate theself-balancing board 10 and the accessory 20 secured thereto in a singlelocation if one control lever 76 is pivoted to pivot the correspondinglateral foot-deck end 14 by an angular disposition in one direction, andif the other control lever 76 is pivoted to pivot the other lateralfoot-deck end 14 by the same angular disposition in the oppositedirection.

As the axis of pivoting of the lateral foot-deck end, typically the sameas the rotation axis for the wheels for split foot-deck designs, isdisplaced from the control pivot axis P about which the interfacemembers 88 pivot, the accessory 20 can be subject to tension anddistortion forces when the angular position of one control lever 76differs significantly from the angular position of the other controllever 76. These tensions and distortion forces can cause the interfacemember 88 to twist on the foot-deck 13 if it is only permitted to pivotabout the control pivot axis P; that is, to have one degree of freedomof movement. This twisting can leave undesirable marks on the foot-deck13 of the self-balancing board 10, and increase the resistance torapidly turning the self-balancing board 10.

FIG. 16 shows the accessory 20 secured to the self-balancing board 10wherein the right control lever 76 a has been pivoted forward anddownward, and the left control lever 76 b is in a neutral position. Inorder to reduce the amount of tension and/or distortion that theinterface member 88 undergoes, the accessory 20 enables the control foot108 to more than just pivot about the control pivot axis CP. Inparticular, the interface member 88 is held generally tightly againstthe foot-deck 13 of the self-balancing board 10, and the control foot108 is permitted to pivot relative to the interface member 88 about thetorque pivot post 104 (that is, a second degree of freedom of movement)to reduce tension and torsional forces applied by the interface member88 to the top surface of the foot-deck 13. The lateral ridges 100flanking the top recess 96 of the interface member 88 are features thatact to restrict movement of the control foot 108 within a desired range.As the control foot 108 is somewhat tightly held against the platform 11via the cinch strap 144, it is inhibited from pulling away from theplatform 11 enough to clear the lateral ridges 100. Where the controllevers 76 are pivoted to different angular dispositions and/or differentdirections, such as shown in FIG. 16, the control feet 108 pivot on thepivot axis defined by the torque pivot post 104. As a result, the rightcontrol foot 108 a has pivoted counter-clockwise relative to the torquepivot axis TP and the torque pivot post 104 of the right interfacemember 88 a. The left control foot 108 b, however, hasn't pivotedsubstantially relative to the left interface member 88 b.

By enabling at least two degrees of freedom of movement between thechassis 24 and the interface member 88 and, in particular, rotation ofthe interface member 88 relative to an axis that is normal to thefoot-deck 13 when the assembly 20 is mounted thereon, the chance ofincidental damage to the foot-deck 13 by the foot-deck engagementelement 72, and resistance to pivoting of the control levers 76, can bereduced in some scenarios.

Various other means for enabling two or more degrees of freedom ofmovement of the interface members and the chassis can be employed. Forexample, the foot-deck engagement elements can have interface membersfixed in position relative to them, and the coupling between foot-deckengagement elements and the chassis can allow for the foot-deckengagement elements to both pivot about the control pivot axis and towobble. The wobble would enable the play between the chassis and thefoot-deck engagement elements to compensate for the relative movement ofthe positions along the foot-deck to which the foot-deck engagementelements are secured.

The accessory 20 can be removed from the self-balancing board 10 byreleasing the cinch straps 144 from one of the strap engagement hooks128.

FIG. 17 shows an accessory 150 in accordance with another embodimentthat is a slight variation of the accessory shown in FIGS. 1 to 14, andemploys an interface member 154 that is constructed with thicker ends158 at the front and rear of the interface member 154 on the undersidethereof. A resultant gap 162 is created in the middle of the interfacemember 154. Some self-balancing boards are designed to maintain power tothe motors while sensors in the middle of the foot-decks are triggeredvia pressure on the surface. As these sensors are generally centrallylocated in the foot-deck 13, by only contacting the foot-deck 13proximal to their front and back edges, such self-balancing boards canbe turned off while the accessory 150 is secured thereto. That is, byavoiding contact with a central region of the foot-deck 13 in which thesensors are located when the accessory 150 is positioned thereon,actuation of the sensors can be avoided. The gaps 162 are positioned onthe central region of the foot-deck 13 when the accessory 150 ispositioned thereon.

In some cases, the weight of the control levers can, when unheld, lay ina forward position, creating a forward shift in the center of gravityatop of the foot-deck. This can cause a self-balancing board to commencemoving forward, in the direction of the center of gravity. As a result,it can lead to undesired movement of the accessory and self-balancingboard to which it's secured and possible injury or damage to theaccessory or surrounding objects.

FIGS. 18A and 18B show a portion of another accessory 170 in accordancewith a further embodiment that is a variation of the accessory shown inFIGS. 1 to 14. Positioned beside a rear cross-bar 171 of a chassis ofthe accessory 170 is a control lever 172 has a control lever pivotbracket 174 with a control pivot through-hole 176 extending through it.In addition, the external lateral side of the control lever pivotbracket 174 has two pin-holes 178 passing through it. A pivot bolt 180has a bolt head 182 with a deep slot 184 in its face. A threaded hole186 extends through from a side of the bold head 182 and meets the deepslot 184. A threaded screw 188 is dimensioned to be threadingly receivedwithin the threaded hole 186. A biasing structure in the form of abiasing spring 190 has a cross portion 192, with separate coilsextending in counter directions from its ends. Each of the separatecoils has an angled coil end 194, both of which are generally parallel.

During assembly, the pivot bolt 180 is inserted through the controlpivot through-hole 176 of the control lever pivot bracket 174 andthreaded into the rear cross-bar 171. The pivot bolt 180 is tightenedand the deep slot 184 is aligned generally perpendicular to the desiredneutral resting orientation of the control lever 172. The cross portion192 of the biasing spring 190 is placed into the deep slot 184 and movedtowards the back of the deep slot 190. The threaded screw 188 is thenthreaded through the threaded hole 186 until it encloses the crossportion 192 of the biasing spring 190 within the deep slot 184. Then,each of the angled coil ends 194 are inserted into a corresponding oneof the pin-holes 178 and secured therein, such as by bending, taping,etc.

The biasing spring 190 is thus able to exert a net biasing force (as aresult of the two portions of the biasing spring 190) on the controllever 172 towards an angular position relative to the chassis in whichthe center of gravity of the accessory 170 on the self-balancing boardis sufficiently centered to avoid triggering motion of theself-balancing board in either a forward or a backward direction. Thatis, the foot-deck 13 of the self-balancing board 10 is not biased awayfrom a generally horizontal orientation when the accessory is positionedthereon. This net biasing force, however, can readily be overcome bymanually pivoting the control levers 172 in a forward or backwarddirection. The biasing spring 190 is sufficiently resilient to maintaina sufficient net biasing force on the control levers 172 over thelifetime of the accessory 170.

While, in this illustrated embodiment, the biasing structure is a singlespring element, more than one biasing spring can be employed. Further,other types of biasing structures can be employed. For example, leafsprings can be employed so that pivoting of the control levers bends theleaf springs, thereby causing them to exert a biasing force on thecontrol levers towards an angular position in which the center ofgravity of the accessory on the self-balancing board is sufficientlycentered. In another example, compressible members coupled to the pivotbolt can apply a biasing force on the control levers when they arepivoted away from an angular position in which the center of gravity ofthe accessory on the self-balancing board is sufficiently centered.

In other embodiments, biasing structures can be employed to bias thefoot-deck engagement elements relative to the chassis so that, when theaccessory is positioned on a self-balancing board, the foot-deck of theself-balancing board is unbiased away from a generally horizontalorientation.

FIG. 19 shows an accessory 200 in accordance with another embodiment.The accessory 200 has a chassis 204 that includes two parallellongitudinal extension tubes 208 that are slidingly received within twoparallel telescoping longitudinal tubes 212 and lockable at a number ofpositions via a locking knob 216. The two parallel telescopinglongitudinal tubes 212 extend from a rear cross-bar 220 at the rear. Thetwo longitudinal extension tubes 208 are joined to a pivot bracket 224.A head assembly 228 is coupled to the pivot bracket 224 and pivots abouta vertically mounted head pivot bolt 232. The head assembly 228 includesa front cross-bar 236 having a pair of foot rests 240 at its lateralends. A front wheel assembly 244 is mounted in a fixed orientation atthe bottom of the head assembly 228. A seat 248 is mounted on thetelescoping longitudinal tubes 212 via a seat mounting bracket 252.

A master foot-deck engagement element 256 at a first lateral end of therear cross-bar 220 is coupled via a bridging member in the form of alinkage that passes through the rear cross-bar 220 to a slave foot-deckengagement element (not shown) so that they pivot together about acontrol pivot axis P. The master foot-deck engagement element 256 issimilar to the foot-deck engagement elements of the accessory shown inFIGS. 1-14. It includes an interface member 260 and a control foot 264that rests within a top recess thereof and pivots about a pivot postextending vertically from the interface member 260. The control foot 264has a positioning arch 268 that has laterally extending position teetharound its periphery. A strap engagement hook 272 is formed on the topsurface of the control foot 264 proximal to its front and rear ends. Theslave foot-deck engagement element also has an interface member and acontrol foot similar to those of the master foot-deck engagementelement, except that it does not have a positioning arch.

A control lever 276 is pivotally coupled to the positioning arch 268 viaa control lever pivot bracket 280 so that it pivots around a controlpivot axis P. The control lever 276 has a control grip 284 at its otherend to enable a rider to grasp and control pivoting of the control lever276 with one hand. The angular position of the control lever 276 can beadjusted via two positioning lock release levers.

The accessory 200 can be secured to a self-balancing board such as theone illustrated in FIG. 1 in the same way that the accessory 20 of FIGS.1 to 14 is secured to it. The accessory 200 uses the self-balancingboard as a motor means for propelling the combined accessory 200 andself-balancing board. By pivoting the control lever 276, the rider cancontrol the pitch of the lateral foot-deck ends of the self-balancingboard. As both the master foot-deck engagement element 256 and the slavefoot-deck engagement element are pivotally fixed relative to each other,pivoting of the control lever 276 pivots the pitch of both lateralfoot-deck ends simultaneously. As a result, both wheels accelerate ordecelerate in the same direction at the same time. Steering of theaccessory 200 is achieved by the rider pivoting the head assembly 228using their feet. As the front wheel assembly 244 is fixed relative tothe head assembly 228, it pivots with the head assembly 228 to steer theaccessory 200 and the self-balancing board to which the accessory 200 issecured.

While control levers are employed in the above described embodiments tocontrol the orientation of the lateral foot-deck ends of theself-balancing board, other control members can be employed for thispurpose. For example, an accessory can have a chassis that is hingedpartway along its longitudinal length and has a biasing structure forbiasing a front chassis portion relative to a rear chassis portion aboutthe hinge. For example, the front chassis portion may be biased relativeto the rear chassis portion to a position where the chassis portionsmeet at an angle of 150 degrees, and the biasing structure permitspivoting of the front chassis portion and the rear chassis portion tolessen or greaten the angle between them. The front chassis portion canhave a wheel and foot rests proximal to its front end, and the rearchassis portion can have a seat proximal to its rear end. Further, therear chassis can include control members in the form of frame elementsthat are coupled relatively fixedly to two foot-deck engagement elementsthat can be positioned on the foot-deck of a self-balancing boardproximal to its lateral ends. By extending their legs, a rider can causethe front and rear chassis portions to straighten, thereby reorientingthe foot-deck engagement portions attached to the control members of therear chassis portion, and the foot-deck ends of the self-balancing boardwith it to cause the self-balancing board to propel forward. Similarly,by pulling their feet closer, a rider can cause the front and rearchassis portions to contract, reducing the angle between them, therebyreorienting the foot-deck engagement portions attached to the controlmembers of the rear chassis portion, and the foot-deck ends of theself-balancing board with it to cause the self-balancing board toreverse.

While the accessory in the embodiments described above has a singlewheel assembly, it may be desirable to employ two or more wheels on theaccessory, thereby providing four or more wheels on the combinedaccessory and self-balancing board.

Other types of travel surface-contacting elements to facilitate travelof the chassis over a travel surface other than wheels can be employedfor the accessory. For example, the accessory can be fitted with a skirunner that could be used over indoor flooring, grass, snow, etc. Inanother embodiment, a tank track could be deployed on the accessory.

The length and orientation of the control lever(s) may be made to beadjustable in a variety of manners, such as the angle that they extendfrom the pivot brackets (the angular position), the angle at which theyextend laterally away from a vertical axis, etc.

While, in the above-described embodiments, the control lever is separatefrom the foot-deck engagement element, in other embodiments, the controllever and the foot-deck engagement element can be manufactured as aunitary element or assembly. While the angular position of the controllevers would not be adjustable relative to the foot-deck engagementelements, production costs may be reduced and product durability may beincreased in some scenarios.

Where, in the above-described and illustrated embodiments, cinch strapsare used to releasably secure the accessories to self-balancing boards,other means for securing the accessory to the self-balancing board canbe employed. For example, the accessory may be bonded to the platform,although this approach would not allow the self-balancing board to beseparable from the accessory. In another example, the accessory may bemagnetically coupled to the self-balancing board via a magnetic element,thereby enabling the accessory to be removed from the self-balancingboard when desired. Further, the foot-deck engagement elements maysimply rest on the self-balancing board without securing the accessorythereto. In a further embodiment, the foot-deck engagement elements canreleasably clamp onto the platform of the self-balancing board.

The accessories can be made to accommodate self-balancing boards ofvarious shapes and sizes.

The seat can be made unitarily with the chassis in some embodiments.

Various types and configurations of chasses can be employed to provide aplatform.

More sophisticated pedal or foot straps can be employed to furthersecure the rider.

Persons skilled in the art will appreciate that there are yet morealternative implementations and modifications possible, and that theabove examples are only illustrations of one or more implementations.The scope, therefore, is only to be limited by the claims appendedhereto.

The invention claimed is:
 1. A vehicle assembly, comprising: aself-balancing board, having the self-balancing board comprising afoot-deck having two lateral foot-deck ends, each lateral foot-deck endbeing coupled to a motor that drives a wheel in response to anorientation of the lateral foot-deck end relative to a horizontal plane;and an accessory including: a chassis; at least one travelsurface-contacting element coupled proximal to a first longitudinal endof the chassis to facilitate travel of the chassis over a travelsurface; a seat coupled to the chassis and configured to support aperson; a first foot-deck engagement element proximal to a secondlongitudinal end of the chassis distal to the first longitudinal end andconstructed to engage the foot-deck of the self-balancing board proximalto the first lateral foot-deck end; a second foot-deck engagementelement proximal to the second longitudinal end of the chassis andconstructed to engage the foot-deck of the self-balancing board proximalto the second lateral foot-deck end; and at least one control membercoupled to the first foot-deck engagement element and the secondfoot-deck engagement element to control the orientation of the lateralfoot-deck ends relative to a horizontal plane via the first foot-deckengagement element and the second foot-deck engagement element.
 2. Avehicle assembly according to claim 1, wherein the at least one controlmember comprises at least one control lever being coupled to the firstfoot-deck engagement element and the second foot-deck engagement elementto control pivoting of the first foot-deck engagement element and thesecond foot-deck engagement element.
 3. A vehicle assembly according toclaim 2, further comprising a bridging member coupled to the firstfoot-deck engagement element and the second foot-deck engagement elementto control pivoting of the first foot-deck engagement element and thesecond foot-deck engagement element relative to one another.
 4. Avehicle assembly according to claim 3, wherein the at least one controllever comprises a first control lever coupled to the first foot-deckengagement element and the second foot-deck engagement element tothereby control simultaneous pivoting of the first foot-deck engagementelement and the second foot-deck engagement element.
 5. A vehicleassembly according to claim 2, wherein the at least one control levercomprises a first control lever coupled to the first foot-deckengagement element and a second control lever coupled to the secondfoot-deck engagement element.
 6. A vehicle assembly according to claim5, wherein the first foot-deck engagement element is independentlypivotable relative to the second foot-deck engagement element about acontrol pivot axis that is generally parallel to the rotation axis ofthe wheels of the self-balancing board.
 7. A vehicle assembly accordingto claim 6, wherein each of the first foot-deck engagement element andthe second foot-deck engagement element comprises an interface memberconstructed to interface with the foot-deck proximal to one of thelateral foot-deck ends and having at least two degrees of freedom ofmovement relative to the chassis.
 8. A vehicle assembly according toclaim 7, wherein each of the first foot-deck engagement element and thesecond foot-deck engagement element further comprises a control footthat is pivotable relative to the chassis about the control pivot axisthat is generally parallel to the rotation axis of the wheels of theself-balancing board and is movably coupled to the interface member toenable movement of the control foot relative to the interface member. 9.A vehicle assembly according to claim 8, wherein the control foot ispivotably coupled to the interface member about a torque pivot axis thatis generally perpendicular to the control pivot axis.
 10. A vehicleassembly according to claim 9, wherein the first foot-deck engagementelement is constructed to secure to the foot-deck of the self-balancingboard proximal to the first lateral foot-deck end and the secondfoot-deck engagement element is constructed to secure to the foot-deckof the self-balancing board proximal to the second lateral foot-deckend.
 11. A vehicle assembly according to claim 10, wherein the firstfoot-deck engagement element is constructed to releasably secure to thefoot-deck of the self-balancing board proximal to the first lateralfoot-deck end and the second foot-deck engagement element is constructedto releasably secure to the foot-deck of the self-balancing boardproximal to the second lateral foot-deck end.
 12. A vehicle assemblyaccording to claim 11, wherein each of the first foot-deck engagementelement and the second foot-deck engagement element comprises a fastenerfor releasably securing the interface member against the foot-deck. 13.A vehicle assembly according to claim 12, wherein the interface membercomprises the fastener.
 14. A vehicle assembly according to claim 13,wherein the fastener comprises at least one of a strap, a clamp, and amagnetic element.
 15. A vehicle assembly according to claim 14, whereinthe control foot is pivotally secured to the interface member.
 16. Avehicle assembly according to claim 12, wherein the fastener couplesdirectly to the control foot.
 17. A vehicle assembly according to claim16, wherein the fastener comprises at least one of a strap, a clamp, anda magnetic element.
 18. A vehicle assembly according to claim 17,wherein the interface member comprises features restricting movement ofthe control foot relative to the interface member within a desiredrange.
 19. An accessory for a self-balancing board, the self-balancingboard comprising a foot-deck having two lateral foot-deck ends, eachlateral foot-deck end being coupled to a motor that drives a wheel inresponse to an orientation of the lateral foot-deck end relative to ahorizontal plane, the accessory comprising: a chassis; at least onetravel surface-contacting element coupled to the chassis to movablysupport the accessory on a travel surface; a seat coupled to the chassisand configured to support a person; a first foot-deck engagement elementcoupled to the chassis at a point spaced from at least one travelsurface-contacting element and constructed to engage the foot-deck ofthe self-balancing board proximal to the first lateral foot-deck end; asecond foot-deck engagement element coupled to the chassis at a pointspaced from at least one travel surface-contacting element andconstructed to engage the foot-deck of the self-balancing board proximalto the second lateral foot-deck end; and a first control lever coupledto the first foot-deck engagement element and a second control levercoupled to the second foot-deck engagement element, wherein the firstand second control levers are movable to control the orientation of thelateral foot-deck ends relative to a horizontal plane via the firstfoot-deck engagement element and the second foot-deck engagementelement, wherein the first foot-deck engagement element is independentlypivotable relative to the second foot-deck engagement element about acontrol pivot axis that is generally parallel to the rotation axis ofthe wheels of the self-balancing board, wherein each of the firstfoot-deck engagement element and the second foot-deck engagement elementcomprises an interface member constructed to interface with thefoot-deck proximal to one of the lateral foot-deck ends and having atleast two degrees of freedom of movement relative to the chassis.